George smith



Patented Sept. 1'7, 1889.

25512525: r ld wjei-gzmtnr Q0:

UNITED STATES PATENT OFFICE.

GEORGE SMITH, OF GLASGOW, COUNTY OF LANARK, SCOTLAND.

PRIMER-TUBE FOR DYNAMITE CARTRIDGES.

SPECIFICATION forming part of Letters Patent No. 411,206, datedSeptember 17, 1889. Application filed June 28,1888. Serial No. 278,281.(No model.) Patented in England June 25, 1886, No. 8,368; in FranceDecember 9, 1886, No. 180,179; in Belgium December 10, 1886,

No. 75,562; in Germany December 11, 1886, No. 41,322; in

Canada January 19, 1887, No. 25,813, and in Austria-Hungary August 9,1887, No. 1,073 and No. 34,645.

To all whom it may concern.-

Be it known that I, GEORGE SMITH, a subject of the Queen of GreatBritain and Ireland, residing at Glasgow, in the county of Lanark,Scotland, have invented an Improved Detonator Tube for CartridgesCharged with Dynamite or Similar Explosive, of which the following is aspecification.

An invention on which the present invention is an improvement has beenpatented to me in a British patent dated June 25, 1886, No.

8,368; in a French patent dated December 9, 1886, No. 180,179; in aBelgian patent dated December 10, 1886, No. 75,562; in a German patentdated December 11, 1886, No. 41,322; in a Canadian patent dated January19, 1887, No. 25,813, and in an Austria-Hungarian patent dated August 9,1887, No. 1,073 and No. 34,645.

My improved detonator-tube is made of thin' steel instead of copper,which has hitherto generally been employed. It has been proposed to makecartridge-shells (which are analogous to detonator-tubes) of thin steel,but not in the manner and with the accessories constituting thecombination which I claim as my present invention. Copper has been usedfor making percussion-caps, detonator-tubes, and cartridge-shells,because of its being less liable than iron or steel to produce sparkswhen accidentally struck or scratched by a hard substance. In order toremove the liability to produce sparks from my steel detonator-tubes, Ielectroplate them with a thin coating of copper when they are otherwisefinished.

In describing my invention I will refer to figures on the accompanyingsheet of explanatory drawings, these figures showing the detonator-tubesas considerably enlarged.

My improved detonator-tube is at an early stage of its format-ion of theform shown in Figure 1. It is a tube A, with one end B closed, and ismade, in a well-known manner, by forcing the steel through a die. Inmaking a tube the end 13 is unavoidably made thicker than the sides A,whereas it is desirable that While there should be an end to retain thefulminant or detonating explosive in the tube, that end should be Weakerthan the sides in order that the explosion should be mainly directedthrough the end, in order to act with certainty on the dynamite or otherexplosive forming the main charge of the cartridge into which thedetonator-tube is inserted. In the next stage of the tubes formation anopening 0 is formed by punching out the end B, but so as to leave acontraction or inwardly-bent flange D round the edge. Afterward the endopening 0 is closed by a disk E, of very thin copper or other suitablematerial, introduced from the other end of the tube. The fulminant ordetonating explosive is put into the tube so as to occupy about half itsinterior next the disk E, and when made ready for use the end of thefuse is inserted into the open end of the tube-the upper endas shown inthe drawings.

By forming the detonator-tube of thin steel in the manner described I amenabled to make it not only at less cost than when made of copper, but,also with sides which from their greater strength cause the explosion totake effect in the desired direction and with increased certainty.

WVhat I claim is A detonator tube for cartridges charged with dynamiteor similar explosive, and consisting of a tube of thin steel having anopen but contracted inner end, a plating of thin copper upon this tube,and a disk of thin material closing the inner end, the said disk beinginserted at the outer end and retained by the contraction at the innerend, substantially as and for the purposes herein set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

GEORGE SMITH.

Vitnesses:

EDMUND HUNT, DAVID FERGUSON.

